**Ruth Britto**

**Associate Professor in Theoretical Physics**

**Fellow of Trinity College Dublin**

Dublin 2

Ireland

+353 1 896 3945

2022-23:
On sabbatical leave at the Institute for
Advanced Study (Princeton, USA).

**Research**

Scattering amplitudes play a key role in
high-energy physics. Not only do they describe the actual scattering taking
place in collider experiments--of current importance in the era of the Large
Hadron Collider (LHC)--but they also illuminate the formal aspects of quantum
field theories, such as divergent behavior or integrability. Amplitudes are
thus useful both practically and formally, but their availability is limited by
the difficulty of computing them.

As the number of particles in the scattering process
increases, or the perturbative expansion is carried out to higher order, the
traditional technique of Feynman rules fails to be feasibly implementable. This
difficulty has prompted the innovation of new techniques. Notable among these
are *on-shell* techniques, in
which the basic building blocks are complete amplitudes, rather than
fundamental interactions. The on-shell framework has surpassed traditional
Feynman diagram expansions, both in delivering new results and in expressing
them in formulas that are not only compact, but also deeply illuminating. My
research develops the on-shell framework to incorporate all theories and
configurations of physical interest, building upon recent developments in pure
mathematics.

**Innovative
Training Network Scattering Amplitudes:
from Geometry to Experiment [SAGEX]**

2018-2022. A network of eight European beneficiary
institutions hosting 15 PhD students in the field of scattering amplitudes, in
cooperation with international partners from academia and industry.

**Publications**

Full
list of publications on INSPIRE

Lecture
notes: Constructing
scattering amplitudes

Review
articles:

· Mathematical structures in
Feynman integrals, with S. Abreu and C. Duhr. (Chapter 3 of The SAGEX Review on Scattering
Amplitudes)

· Loop
amplitudes in gauge theories: modern analytic approaches